Acute pain management in patient on intrathecal opioid infusion for chronic pain.

Intraspinal drug delivery (IDD) has been increasingly utilized since 1980s, initially in patients with cancer pain, and subsequently in patients with intractable, chronic, nonmaligmant pain. By infusing a small amount of opioid into the cerebrospinal fluid in close proximity to the receptor sites in the spinal cord, profound analgesia may be achieved while sparing some of the side effects due to systemic opioids. The introduction of intrathecal opioids has been considered one of the most important breakthroughs in pain management in the past 3 decades. However, with the ever-increasing patient population nowadays, having implanted drug delivery pumps for their chronic pain, there appears to have a need for addressing acute pain management issues in this group of patients. The important questions to ask are: When patients, on intrathecal opioid infusion for chronic pain, go for surgical procedures, such as hip replacement or knee replacement, etc., what should be done with their intrathecal opioid regimen? Do we go up, come down, continue, or discontinue their routine intrathecal opioid infusion before surgery? What should we do for their postoperative pain? Can we still use routine modalities such as intravenous patientcontrolled analgesia (IV PCA) or epidural analgesia in such patients for their postoperative acute pain control? What about using intrathecal opioid for acute pain management since the patients already have intrathecal catheters implanted? These are very pertinent and practical questions to raise, as we are encountering these situations more often than ever, because of the ever-increasing patient population with implanted intrathecal infusion pumps. There has been no literature, guidelines, consensus statements, expert opinions, or even recommendations published, to the best of my knowledge, pertaining to these clinical situations. My own clinical approach has been keeping the intrathecal opioid infusion the same preand postsurgery, while utilizing IV opioid PCA for post operative pain. This approach has also been utilized by some other interventional pain specialists who manage chronic pain patients with implanted pumps (J. Patrick Couch, MD, Rinoo V. Shah, MD, Srinivas Chiravuri, MD, personal communications). It seems reasonable to assume that the routine intrathecal infusion satisfies the opioid requirement for the chronic pain component, while the IV opioid PCA meets the additional opioid requirement for acute pain due to surgery. However, whether or not this assumption represents “standards of care” awaits further investigation. Over the past 3 years, over 20 patients from my clinic, while on the same routine intrathecal opioid infusion therapy for chronic non-malignant pain, underwent surgical procedures such as lumbar fusion, cervical fusion, total hip replacement, total knee replacement, and received IV opioid PCA (morphine, hydromorphone) for post-operative pain, without encountering any complications or side effects of opioid overdose. Nonetheless, it is still unclear what should be done in situations of above, even to interventional pain specialists who routinely manage patients with implanted pumps, not to mention those orthopedic surgeons who have no experience dealing with patients with implanted pain pumps for chronic pain, because of the lack of information or experience. There were quite a few times, in the past a few years, that I was consulted for preand post operative pain management because of surgeons feeling unsure what to do before and after operating on patients with implanted intrathecal opioid pumps. ASIPP has been a true leader in establishing evidence-based practice guidelines in interventional pain management. In my opinion, the area of “Acute Pain Management in Patient on Intrathecal Opioid Infusion for Chronic Pain” is still “blank” and needs further investigation, due to the increasing popularity of intrathecal pain pumps used for varieties of chronic painful states. Hopefully, this correspondence will